Pin feed tractor mechanism



April 21, 1970 H. E. HEPP ET AL PIN FEED TRACTOR MECHANISM Filed May 5, 1968 FIG.4 39

FIG.6

FIG.5

INVENTORS HAROLD E. HEPP 8| ROGER W. BISER BY 2? A M,

THEIR ATTORNEYS United States Patent 3,507,431 PIN FEED TRACTOR MECHANISM Harold E. Hepp, Dayton, and Roger W. Biser, Troy,

Ohio, assignors to the National Cash Register Company, Dayton, Ohio, a corporation of Maryland Filed May 3, 1968, Ser. No. 726,396 Int. Cl. B65h 17/38 US. Cl. 226--74 16 Claims ABSTRACT OF THE DISCLOSURE An endless drive means for advancing paper or other record material through a printing station, including a toothed flexible belt trained on sprockets and carrying spaced links and pins for engaging the paper, the links being positioned to embed alternate teeth of the belt. The drive means has guide elements disposed on either side of the belt to maintain the pin-carrying links in a straight path between the sprockets for optimum driving relationship with the paper.

BACKGROUND OF THE INVENTION The prior art shows and describes various mechanisms for moving paper and paper forms or other like record material through a printing station or machine wherein an imprint is made or transferred onto the paper. Previous mechanisms have included pin-type feed devices carried on a chain of pivotally connected links and driven by means of a sprocket wheel, as disclosed in United States Patent No. 2,158,585, issued May 16, 1939, on the application of Carl R. Mabon; flexible endless belts or bands having feed pins mounted on brackets and driven by sprockets or drums, as shown in United States Patent No. 2,171,003, issued Aug. 29, 1939, on the application of Carl R. Mabon; flexible chains having interconnected links each carrying an axially tiltable driving pin thereon, as seen in United States Patent No. 2,286,084, issued June 9, 1942, on the application of Louis F. Hageman; and endless chains with links supporting a number of brackets each having a driving pin thereon, as disclosed in United States Patent No. 3,015,425, issued Jan. 2, 1962, on the application of Harold P. Wicklund. Materials used in these prior art, pin feed type, devices have included metal, rubber, nylon, and plastic for the various parts, the material selected depending upon the advancements made in the state of the art and the desired function. The chain and sprocket type feed mechanism are subject to wearing of the individual links and connector pins, which changes the center-to-center distance between the pins driving the paper, with .resultant deformation of the apertures in the paper and loss of exact control of the paper traveling through the machine. While many of these mechanisms have been satisfactory, improved devices and materials are desired as the speed of the machines is increased to fulfill the demand for higher volume output.

SUMMARY OF THE INVENTION The present invention relates to tractor or like drive mechanism for advancing paper or other record material through a printing station. Typically, the paper is perforated at spaced intervals along each side, and the drive mechanism on each side of the paper includes pins which enter the perforations and carry the paper into position for the recording of data thereon. While the present invention will be described as adaptable for feeding paper through a high'speed printer, the principles used in the design of the device, especially the construction of the belt employed, could be applied to other feedtype mechanisms. The invention is utilized with a tractor ice mechanism having drive means in the form of a splined shaft, and a second or idler shaft for carrying and supporting the mechanism in proper position. The splined shaft carries a drive sprocket, and the second shaft carries an idler sprocket. A timing belt is trained over the sprockets, the belt being of the flexible type and including links laterally positioned therefrom, the links carrying paper-engaging pins for moving the paper along in its travel through the machine.

In a printer of the type for which this invention is adapted, there are at least two of the drive mechanisms, one on each side of the paper for the purpose of insuring exact control over the paper as it travels through the printing station. Each mechanism is alike except that one is for right hand and the other is for left hand, so that only one will be herein shown and described. Of course, there may be several of the right and left hand tractors provided to properly carry the paper through the machine. The timing belt is of the endless type and includes drive lugs or teeth around the interior periphery thereof, the drive means being so constructed that every other tooth of the belt is embedded in a recessed portion of a link which carries the pin. The belt meshes with the drive and idler sprockets, which are formed with grooves to fit alternate exposed belt teeth and also adjacent links of the embedded teeth. The pin-carrying links, so positioned at every other tooth, are secured to the belt by capturing the belt between each link and a suitable plate affixed thereto.

It is of course extremely important that the pin-carrying links travel in a straight path when in paper-engaging position and also that the links remain parallel aligned, so that the center-to-center distance between pins is maintained to fully engage with the perforations in the paper. A guide plate is secured to the body of the mechanism in a position adjacent the links to maintain the paper at the proper level therewith. A bracket is also provided on the mechanism body and is so positioned that the links ride along and are contained by the bracket when in the paper-engaging position maintaining the links in a straight condition and thus preventing uneven or wavy travel when engaging the paper, as well as providing a means to suppress the tendency of the belt to continue in a curved path after leaving a sprocket. The mechanismbody also includes a raised belt guide ortion along which the links slide in their paper-engaging position.

Control of belt tension by means of an eccentric bushing connected with the support shaft, which, by reason of the particular construction, also serves as the idler shaft, is likewise provided. In this respect, the support shaft does not change location when adjusting the belt tension. A portion of the bushing eccentric to the centerline of the bore supports the idler sprocket and its hearing, so that angular rotation of the bushing changes the center-to-center distance between the driving sprocket and the idler sprocket.

With the above discussion in mind, the principal object of the present invention is to provide an improved tractor mechanism for advancing paper or other record material through a printing station at the higher speeds.

A further object of the invention is to provide a linkcarrying toothed belt cooperating with a sprocket drive wherein the sprocket engages alternate teeth on the belt and also engages adjacent links for driving the belt.

An additional object of the invention is to provide a timing belt for maintaining proper drive and tension on the paper being handled.

A further object of the invention is to provide an endless belt having pin-carrying record material drive links attached thereto and constructed to prevent twisting of the links during the belt travel.

Additional advantages and features of the present invention will become clear and fully understood from a reading of the following description taken together with the annexed drawing, in which:

FIG. 1 is a plan view of an improved pin feed tractor mechanism according to the preferred embodiment of the present invention for moving sheets of record material;

FIG. 2 is a view in side elevation of the improved tractor mechanism taken on line 22 of FIG. 1, with parts being broken away;

FIG. 3 is an end view of the tractor mechanism;

FIG. 4 is a greatly enlarged sectional view taken on line 4-4 of FIG. 1;

FIG. 5 is a perspective view of one of the pin-carrying links employed in the present invention; and

FIG. 6 is a view in section taken on line 66 of FIG. 2.

Referring to FIG. 1, there is shown a top or plan view of a pin feed type tractor mechanism which incorporates the structure of the present invention, the particular tractor shown being of a left hand unit and it being understood that a right hand unit is spaced the width of the paper from the left hand unit. Since these tractor mechanisms are useful for advancing or feeding continuous paper or other record material into or through a station or machine, a plurality of such mechanisms are typically provided to control movement of the paper. The mechanisms are essential to control paper tension and alignment to properly position said paper at the time an operation, such as printing or the like, is performed with respect thereto. In a machine for which the present invention is applicable and for which it will be described, as mentioned above, there are two of these tractor mechanisms spaced on the printer for controlling the movement of the continuous form paper through the printing station. The tractor mechanisms are alike, except that there are left hand and right hand units to insure the precise control of the paper, which is a requirement in the field of higher speed printers. As the printing speed of these machines is increased, the demand for this precise control of the paper in the printing operation has justified the development of the present invention.

The tractor mechanism, generally designated as 10 in FIGS. 1, 2, and 3, includes a frame or body 11 of irregushape having spaced bores therethrough, one bore 12 being for a drive shaft and its associated parts and the other bore 13 being for a support shaft. The bore 12 carries a fixed bearing 14, in which is journaled a hub 15, and the bore 13 carries a fixed bearing 16 and an eccentric bushing 17. A drive shaft 18 of the splined type is fitted through the hub 15, such shaft being connected to a suitable drive means (not shown), and a support shaft 19 runs through the bushing 17the entire mechanism being suitably carried for slidable movement along the several shafts 18 and 19. A pulley 20 is placed on the shaft 18 adjacent the body 11, and internal grooves 20a thereof, in conjunction with associated cap screws 21 received therethrough, provide means for adjustably securing the pulley to the outer face of the hub 15, which is constructed to carry the shaft 18 for driving the pulley 20 in a counterclockwise direction (FIG. 2). A second pulley 22, placed adjacent the bushing 17, is supported on the shaft 19 for idler operation. Of course, suitable spacers, collars, retaining rings, and the like are used to align and make secure the various parts of the mechanism, so that the body 11 and the pulleys 20 and 22 move as a unit along the shafts 18 and 19.

The pulleys 20 and 22 may also be aptly named sprockets, in that each has grooves or recesses in its outer periphery, there being first or deep recesses 23 and second or shallow recesses 24. As seen in FIG. 2, the first recesses 23 are formed, circular depressions, and the second recesses 24 are sloped-wall or near gear-tooth-shaped deressions, it being noted that such recesses alternate b tween the deep 23 and shallow 24 types. In other words, every other recess is circular, and the recess between the circular ones is generally sloped-wall-shaped for purposes to be described. Each sprocket is made of a synthetic material to combine the qualities of strength and light weight in the drive mechanism.

An endless belt 32 is placed or trained over the sprockets 20 and 22, such belt being made of a flexible material such as rubber and being formed with equally spaced lugs or teeth 33 on one side thereof, in the present embodiment on the interior periphery, for engaging and meshing with recesses in the sprockets. The lugs or teeth 33 are identical and assume a shape cooperative with the shallow or sloped-wall-shaped recesses 24 in the sprockets 20 and 22. Secured to the belt 32 are a plurality of links, generally designated as 34, each comprising, as best seen in FIGS. 4, 5, and 6, upstanding side portions 35 and 36, a central connecting portion 37, and an extending arm portion 38 carrying an upstanding pin 39. Each link it also made of a synthetic material compatible with the sprocket material and thus combines the qualities of strength and light weight so important for good performance in highspeed record material advancing operations. The side portions 35 and 36 are generally rectangular, but each has a section removed therefrom to form an upper cutout 40 to be used for the purpose of attaching the link 34 to the belt. As per FIG. 5, the several cutouts 41) leave four upstanding projections 41, all for the purpose to be described later in relation to the traveling of the belt between the sprockets.

The central connecting portion 37 of each link 34, as seen in FIGS. 4 and 5, is molded or otherwise formed with a semicircular lower surface 42 and has a generally slopedwall-shaped groove or recess 43 in the upper side opposite the circular surface. It should be noted from the sectional View of FIG. 4 that the recess 43 receives therein a lug or tooth 33 of the belt 32 and that the rounded portion 42 seats in the deep, circular recess in each of the sprockets 20 and 22, as seen in FIG. 2. Adjacent the link recess 43 are top portions 44 and 45, which are slightly curved to correspond to the radius of the belt 32 as it travels around the sprockets. As mentioned previously, the links are secured to alternate teeth 33 of the belt 32, and, since they mate with and seat in the circular depressions on the driving sprockets 20, they serve as an aid to the remaining such teeth 33 in driving the belt. This provides a closer and more exacting fit betweenthe belt and the sprocket, so as to avoid lost motion and back-lash in the mechanism when performing in a high-speed stop-and-go operation.

As also mentioned previously, the cutout 40 is made available in the formation of the link 34 for attaching the link to the belt 32. Each of the side portions 35 and 36 includes a small upstanding pin 48 as an integral part of the portion and centrally located in its respective cutout 40. A plate 49, of a length to extend between the link side portions 35 and 36, of a width to fit snugly within the side portion cutouts 40, and having apertures near its ends for alignment with the several upstanding pins 48, is, in the manner now described, also available for attaching the link 34 to the belt 32.

Recalling now the overall drive belt arrangement discussed above, the links 34 are placed on the belt 32 in such a manner that the central portion of adjacent links seats or embeds every other lug or tooth on the belt. With each link so placed, the plate 49 is pressed within the link cutouts 40 and over the outer peripheral surface of the belt 32, the pins 48 protruding the apertures 50. The pins 48 are then peened, or upset, as seen in FIG. 4, to firmly secure the links to the belt, thus completing the belt assembly. Both the embedment of the belt tooth 33 in the link recess 43 and the capturing of the belt by the plate 49 insure that the link will not tend to twist in a longitudinal direction with the belt.

In FIG. 6 is shown a sectional view through one portion of the tractor body 11, also through the belt 32, and.

viewing a link 34 in elevation when in the paper-engaging position. The paper and the paper guide have been omitted from this view. As further illustrated in FIG. 1, the body 11 includes, as an integral part thereof, an upper rail portion '60, along which the links 34 ride when traveling between the sprockets. Such rail 60 is formed so as to provide a track for the link side portions 35 and 36 to ride along when the links move across the top of the tractor body 11, the side portions 35 and 36 engaging the sides of the rail. This rail maintains all the links 34 in both a fixed parallel and side-by-side aligned relationship when moving along the upper surface of the tractor body 11. The rail portion 60, shown dotted in FIG. 1, has tapered ends to guide the links into such fixed relationship immediately upon reaching the belt run extending between the sprockets 20 and 22. While such rail provides the described alignment of the links, in that the links are maintained normal to the belt, additional means are provided in the form of an L-shaped bracket 62 secured by one leg to the side of the mechanism, as with screws 64, and having its other leg so positioned as to maintain the links 34 in a straight or planar position throughout the period when the pins thereof are engaged with the paper. FIGS. 2 and 3 show such bracket 62, it being noted in FIG. 3 that space is provided between the bracket and the top of the link projections 41 sufficient only for the links to slide therealong. The bracket 62 also includes sloping or beveled end portions 65 and 66 (FIG. 2) to insure that the projections 41 of the links are readily received thereunder when coming off the sprocket 22. Adjustment of the bracket 62 up or down in relation to the tractor body 11 is of course available by means of the screws 64 to obtain the proper tolerance and fit for the links as they move along the tractor body. A paper guide 68, secured to the top surface of the body 11 (FIG. 1), is so positioned that the paper 70 or other record material employed (FIG. 3) is thereby maintained in the proper elevation with respect to each of the pincarrying links. A cover plate 72, shown in phantom in FIG. 1, is placed in the usual manner over the paper 70 to maintain it in position on the link pins 39 throughout the time of its engagement therewith.

As mentioned above, the support shaft 19 is carried by the eccentric bushing 17 provided in the tractor body 11. With this, belt tension can be maintained by turning the bushing, which supports the shaft, and which thus maintains proper tension on the paper being advanced through the machine. The use of such an eccentric element for carrying the shaft 19 eliminates the need for a separate support shaft, which, of course, is an advantage by reducing the mass to be driven in high-speed operations. Angular rotation of the bushing 17 can be performed by use of a spanner-type tool in a notch 71 provided therein (FIGS. 1 and 3), and a set screw inserted through the body 11 to impinge on the bushing effectively maintains its desired setting after adjustment for proper belt tension.

In the operation of the tractor mechanism, the link 34 carrying belt 32 and the sprockets 20 and 22 are assembled on the driving and supporting shafts 18 and 19. Upon rotation of the driving shaft 18, the sprocket 20 is turned, and the belt is driven by the standard teeth 33 thereof being engageable with the corresponding sloped-wall-shaped recesses 24 in the sprocket, and also by the circular central portion 37 of the links being engageable with the circular recesses 23 in the sprocket. Upon this rotation of the driving shaft and the sprocket, the belt 32 is driven along the paper-engaging side of the tractor body 11, the links 34 being maintained parallel and also in a straight line, so that there is no wavy motion upon engagement of the pins 39 thereof with the apertures in the paper 70. The pitch of the belt 32 is so selected that the spacing of the links 34, when attached thereto, will be equal to the spacing between adjacent apertures in the margin of the paper being advanced. The

rail 60 and the bracket 62 provide guide means permitting the belt to be driven at high speeds, with the link pins in proper position to move the continuous form paper through the printing station.

It is thus seen that herein shown and described is an improved pin feed tractor mechanism incorporating a timing belt which fulfills many advantages of and includes desirable features for high-speed printing operations. Although a preferred embodiment has been perfected, variations on the present invention may occur to those skilled in the art, and it is to be understood that all such variations are contemplated as being within the scope of the invention.

What is claimed is:

1. A pin feed device for controlling the movement of record material having spaced apertures therein; including an endless belt having a plurality of teeth on one side thereof, links extending from said belt, each of said links having:

a pin thereon adaptable to engage with one of the apertures in the record material, said links being spaced to be engageable with every other tooth of said belt, and

means for retaining said links in engagement with said every other belt tooth.

2. A device in accordance with claim 1 wherein each of said links includes a central portion having a recess therein for mating with one of the teeth on said belt.

3. A device in accordance with claim 2 wherein each of said links includes a plate member for maintaining the belt tooth in the central portion recess.

4. A tractor mechanism for advancing record material having marginal spaced apertures therein; said mechanism including:

a body portion,

a drive shaft journaled in the body portion,

a support shaft spaced from the drive shaft journaled in the body portion,

means for driving the drive shaft,

a sprocket rotatably fixed to said drive shaft,

a sprocket rotatably free on said support shaft,

a toothed endless belt trained around said sprockets and positioned to be driven for advancing and controlling the record material,

a plurality of links secured to every other of the teeth of said belt and adaptable to cooperate with said drive sprocket, each of said links defining a pin engageable with one of said record material marginal apertures,

guide means on the body portion of containing the record material in pin-engaging position during travel therealong, and

means connected to said body and adjacent said links for maintaining said belt in a straight line in the pin engageable travel of the record material along the guide means.

5. A mechanism in accordance with claim 4 wherein each of said sprockets has recesses on the periphery thereof and every other recess engages with an adjacent link on the belt.

6. A mechanism in accordance with claim 4 wherein each of said sprockets has recesses on the periphery thereof and every other recess engages with alternate teeth on the belt.

7. A tractor feed mechanism for advancing edge perforated record material through a printing station, including:

a body portion,

a driving shaft and a driven shaft journaled in the body portion and spaced one from the other,

operating means for said driving shaft,

a drive sprocket and a driven sprocket on the respective shafts,

a flexible belt element trained around the sprockets, said element having a plurality of spaced teeth on one side thereof for engaging with said drive sprocket to be driven thereby,

a plurality of rigid links connected to the belt element, each of said links extending from said element and having a pin secured at one end thereof for engaging with a perforation of the record material, and each of said links including a central portion having a recess therein seating over a tooth of said element for maintaining the links in parallel alignment, and

means for rigidly securing the links to the belt element.

8. A mechanism in accordance with claim 7 including a guide bracket on the body portion adjacent the belt element, the belt element being slidable along the bracket and contained thereby for moving the links along a straight path in their record-material-engaging travel.

9. A mechanism in accordance with claim 8- wherein said links include projections extending outwardly from the belt element and slidable along the bracket to be contained thereby for maintaining a straight path of travel upon leaving the sprocket and engaging the record material.

10. A mechanism in accordance with claim 8 wherein said bracket includes a sloping portion at one end thereof for guiding the links into a straight path of travel when engaging with the record material.

11. A mechanism in accordance with claim 7 wherein said body portion includes a guide rail engageable by each link for maintaining the links in parallel alignment when in the paper-engaging position.

12. A method of making an endless drive means having a belt with a plurality of teeth on one side thereof, comprising the steps of forming a plurality of links each having a recessed central portion and an arm portion having a pin thereon,

placing said links on said belt so as to embed every other tooth in the link recesses with the pins extending in a direction opposite the teeth, and

securing said links to said belt for maintaining the arm portions normal to the belt.

13. A method of making a drive means in accordance with claim 12 including the additional step of:

forming side portions on each link adjacent the central portion having surfaces on a plane aligned with the surface of said arm portion opposite its pin.

14. A method of making a drive means in accordance with claim 13 including the additional steps of:

forming a plurality of projections on each link as extensions of said side portions, and

attaching a plate between the projections for affixing the link to the belt.

15. In a pin feed tractor mechanism of the type having means for advancing perforated record material through a printing station, said means including a drive shaft and an idler shaft, a body portion carried by said shafts, the idler shaft constituting a supporting shaft and spaced from the drive shaft, a drive sprocket and an idler sprocket on their respective shafts, said sprockets having a plurality of first and second recesses around the periphery thereof, an endless timing belt on said sprockets, said belt having:

a plurality of spaced teeth on one side thereof, a plurality of links secured to said belt and engageable with alternate teeth of said belt to be driven thereby, said first sprocket recesses being formed and spaced to mesh with adjacent links and said sprocket second recesses being formed and spaced to mesh with alternate teeth on said belt, said links including extending arm portions having pins for engaging the perforations of the record material, and

eccentric means for moving the idler sprocket in relation to the drive sprocket to maintain tension On the linkcarrying timing belt.

16. In a mechanism in accordance with claim 15 Wherein said body portion includes a rail for slidably carrying said links, and

a bracket secured to the body portion urging said links against said rail for maintaining said links in a straight plane when traveling in the record-materialengaging position.

References Cited UNITED STATES PATENTS RICHARD A. SCI-IACHER, Primary Examiner US Cl. X.R. 29-428; 226171 

